Measurements of electron density in a SF6arc plasma

Abstract
Several methods for electron number density (Ne) determination in a SF6 arc plasma are successively described: two-wave laser interferometry, Stark broadening of neutral sulphur lines, an original method derived from Stark broadening of a sulphur triplet, the recombination continuum and the derivation of Ne from temperature measurement. The results are in good agreement; they show the existence of departures from LTE due to a demixing effect.